Film and cameras that are all in one, commonly referred to as single-use or one-time-use cameras, have become well known. Typically, the one-time-use camera is a simple point-and-shoot type comprising a plastic main body part which supports a film cartridge in a cartridge receiving chamber, a film take-up spool in a film supply chamber, a fixed-focus taking lens, a film metering mechanism with a rotatably supported metering sprocket that engages the filmstrip, a manually rotatable film advance thumbwheel rotatably engaged with a film spool inside the film cartridge, a single-blade shutter, a manually depressible shutter release button, a rotatable frame counter for indicating the number of exposures remaining for picture-taking, a direct see-through viewfinder, and in some models an electronic flash. A pair of plastic front and rear cover parts house the main body part between them to complete the camera unit. The rear cover part connects to the main body part and/or to the front cover part to make the main body part light-tight. A decorative cardboard outer box or label at least partially covers the camera unit and may have respective openings for the taking lens, the shutter release button, the film advance thumbwheel, the viewfinder, the frame counter wheel, and a flash emission window for the electronic flash.
To use the one-time-use camera, after the photographer takes a picture, he manually rotates the thumbwheel in a film winding direction to rotate the film spool inside the film cartridge, to wind an exposed section of the filmstrip into the film cartridge. The rewinding movement of the filmstrip the equivalent of slightly more than one frame width rotates the metering sprocket in engagement with the filmstrip, to decrement the frame counter to its next lower-numbered setting and to pivot a metering lever into engagement with the thumbwheel to prevent further manual rotation of the thumbwheel. Manually depressing the shutter release button to take another picture pivots the metering lever out of engagement with the thumbwheel to permit renewed rotation of the thumbwheel. When the maximum number of exposures available on the filmstrip are exposed, and the filmstrip is completely wound off the take-up spool and rewound into the film cartridge, the one-time-use camera is given to a photofinisher who tears the outer box off the camera unit, separates the rear cover part from the main body part, and removes the film cartridge with the exposed filmstrip from the cartridge receiving chamber. Then, he removes the exposed filmstrip from the film cartridge to develop the negatives and make prints for the customer, and he forwards the used camera parts to the manufacturer for recycling, i.e. remanufacture.
Typically, during original manufacture or recycling (remanufacture) of the one-time-use camera, a film leader protruding from the film cartridge is attached to the film take-up spool, the film cartridge and the film take-up spool are loaded into the cartridge receiving and film supply chambers, and an intermediate leader section which bridges the film take-up spool and the film cartridge is engaged with the metering sprocket. Then, the front and rear cover parts are connected to the main body part and/or to the front cover part to complete the camera unit. Then, an engageable end of the take-up spool which protrudes from the film roll chamber is rotated to factory prewind substantially the entire length of the unexposed filmstrip from the film cartridge onto the film take-up spool and to rotate the metering sprocket to increment the frame counter to its total-available frame number setting. Lastly, the outer box is placed on the camera unit.
In some models of the one-time-use camera, a metering cam rotatable in response to film advancement after each exposure has at least one tooth for intermittently engaging the frame counter to rotate the frame counter to its next numbered setting when the metering cam is rotated. A problem that may occur is that, each time the tooth is disengaged from the frame counter, the frame counter may undergo a slight rotational creep. As a result, the indicated frame count may become incorrect.